CN112255613A

CN112255613A - Method and system for automatically suppressing navigation radar sea clutter

Info

Publication number: CN112255613A
Application number: CN202011533611.4A
Authority: CN
Inventors: 杨婧; 王伟
Original assignee: Beijing Highlandr Digital Technology Co ltd
Current assignee: BEIJING HIGHLANDR DIGITAL TECHNOLOGY Co.,Ltd.; Sansha Highlander marine Mdt InfoTech Ltd.
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-01-22
Anticipated expiration: 2040-12-23
Also published as: CN112255613B

Abstract

The invention discloses a method for automatically inhibiting navigation radar sea clutter, which comprises the following steps: carrying out grid division on the scanning range; determining a first amplitude value, a noise amplitude value, a sea clutter maximum acting distance of each sector and a sampling point number of each grid contained in a current circle; acquiring a second amplitude value of each grid based on the first amplitude value of the grid around each grid, and processing to obtain a sea clutter basic detection curve; forming a corresponding sea clutter amplitude distribution histogram based on the reserved sampling point amplitude values of each grid; determining an adjustment parameter based on the sea clutter amplitude distribution histogram, and determining a sea clutter gain value; and adding a sea clutter gain value to the sea clutter basic detection curve to obtain a sea clutter detection curve, and smoothing the sea clutter detection curve to obtain a final sea clutter detection curve. The invention also discloses a system for automatically inhibiting the navigation radar sea clutter. The method can provide a reasonable sea clutter gain value and obtain a sea clutter detection curve, effectively inhibits most sea clutter, and obtains a radar image with better quality.

Description

Method and system for automatically suppressing navigation radar sea clutter

Technical Field

The invention relates to the technical field of navigation radars, in particular to a method and a system for automatically inhibiting sea clutter of a navigation radar.

Background

In the related technology, cfar detection is mostly adopted for automatic threshold control of radar, the method calculates the amplitude of echoes around a target by setting a certain number of protection units and reference units, and a final threshold value is obtained according to a set false alarm probability and a method of selecting large units, selecting small units and selecting average units. However, for the navigation radar, the echo of the land or other large targets is also one of the targets to be detected, and the number of protection units of such targets is difficult to set, so that a reasonable sea clutter gain cannot be automatically given.

Disclosure of Invention

In order to solve the above problems, an object of the present invention is to provide a method and a system for automatically suppressing a sea clutter of a navigation radar, which can provide a reasonable sea clutter gain value and obtain a sea clutter detection curve, and can effectively suppress most of the sea clutter to obtain a radar image with good quality.

The invention provides a method for automatically inhibiting sea clutter of a navigation radar, which comprises the following steps:

the method comprises the following steps of performing grid division on a scanning range, dividing the scanning range into a plurality of grids in an azimuth dimension and a distance dimension, wherein each grid comprises a plurality of sampling points, the azimuth dimension is provided with a plurality of circles concentric with a central point, two adjacent concentric circles form a distance ring, the distance dimension is provided with a plurality of rays emitted from the central point, and two adjacent rays form a sector;

determining a first amplitude value of each grid contained in the current circle, a noise amplitude value corresponding to the current circle of antenna rotation, a maximum sea clutter acting distance of each sector and a corresponding sampling point number according to the positions of all sampling points falling in the scanning range of the current circle of antenna rotation;

in the range of the maximum acting distance of the sea clutter of each sector, acquiring a second amplitude value of each grid based on the first amplitude value of the grid around each grid, and processing the second amplitude value of each grid to obtain a sea clutter basic detection curve;

determining whether the amplitude value of the sampling point of each grid is reserved, and forming a corresponding sea clutter amplitude distribution histogram based on the reserved amplitude value of the sampling point of each grid;

determining an adjustment parameter based on the sea clutter amplitude distribution histogram, and determining a sea clutter gain value based on the adjustment parameter;

and for each sector, adding the sea clutter gain value to the sea clutter basic detection curve and performing smoothing treatment to obtain a sea clutter final detection curve.

As a further development of the invention, the scanning range is divided into a plurality of azimuth cells in the azimuth dimension, each azimuth cell is divided into a plurality of range cells in the range dimension,

the method comprises the following steps of determining the first amplitude value of each grid contained in the current circle, the noise amplitude value corresponding to the current circle of antenna rotation, the maximum action distance of the sea clutter of each sector and the corresponding sampling point number according to the positions of all sampling points falling in the scanning range of the current circle of antenna rotation, and comprises the following steps:

determining reference amplitude values of all grids contained in the current circle according to the positions of all sampling points of the current circle, which fall in the scanning range, of the antenna, wherein the reference amplitude value of each grid is obtained by averaging the amplitude values of all the sampling points in the grid;

weighting the amplitude value of each grid to obtain a first amplitude value of each grid,

wherein a and b represent weighting coefficients, respectively,

a reference amplitude value representing a grid where an nth range cell of an mth azimuth cell of the antenna turns the ith turn,

a first amplitude value representing the grid in which the nth range cell of the mth azimuth cell of the i-th turn of the antenna is located,

a first amplitude value representing a grid where an nth distance unit of an mth azimuth unit rotates to an (i-1) th turn;

averaging the amplitude values of all sampling points in each distance ring, and taking the minimum value in the average values of the amplitudes of all distance rings as the current antenna rotationThe noise reference amplitude value of the circle is weighted to obtain the noise amplitude value,

wherein c and d represent weighting coefficients, respectively,

representing the noise reference amplitude value for the i-th turn of the antenna,

representing the noise amplitude value of the i-th turn of the antenna,

representing the noise amplitude value of the i-1 th turn of the antenna;

comparing the first amplitude value of each grid in the distance dimension with the noise amplitude value for each sector, and taking the distance of the first grid in the continuous grids as the maximum acting distance of the sea clutter when the first amplitude values of the continuous grids are all smaller than the noise amplitude value;

weighting the reference sampling points corresponding to the maximum acting distance of the sea clutter in each sector to determine the sampling points corresponding to the maximum acting distance of the sea clutter,

wherein e and f represent weighting coefficients, respectively,

the number of reference sampling points corresponding to the maximum action distance of the sea clutter of the p-th sector of the ith circle of the antenna is represented,

the number of sampling points corresponding to the maximum acting distance of the sea clutter of the p-th sector of the ith circle of the antenna is represented,

and the number of sampling points corresponding to the maximum action distance of the sea clutter of the p-th sector in the i-1 th circle of the antenna rotation is represented.

As a further improvement of the present invention, the obtaining a second amplitude value of each grid based on the first amplitude value of the grid around each grid within the range of the maximum acting distance of the sea clutter of each sector, and processing the second amplitude value of each grid to obtain a sea clutter basic detection curve includes:

weighting the first amplitude values of four grids around each grid to obtain a second amplitude value of each grid,

wherein, in the step (A),

a second amplitude value representing the current grid,

a first amplitude value representing a grid on the current grid,

a first amplitude value representing a grid next to the current grid,

representing a first amplitude value of a grid preceding the current grid,

representing a first magnitude value of a grid subsequent to the current grid;

performing fold line processing on the second amplitude value of each grid, wherein during the fold line processing, if the second amplitude value of the current grid is larger than the second amplitude value of the previous grid, the slope of the fold line between the two grids is 0, and a sea clutter basic detection curve with a declining trend is obtained,

and the amplitude value of the sea clutter basic detection curve of the jth sampling point of the pth sector is represented.

As a further improvement of the present invention, the determining whether amplitude values of all sampling points in each grid are reserved, and forming a corresponding sea clutter amplitude distribution histogram based on the reserved amplitude values of the sampling points includes:

and when a preset condition is met, determining amplitude value reservation of all sampling points in each grid.

As a further improvement of the present invention, the preset conditions include the following two conditions:

in the range of the maximum acting distance of the sea clutter of each sector, for each grid, comparing a second amplitude value of the grid with a detection value of a sea clutter basic detection curve corresponding to a first sampling point falling into the grid, wherein the subtraction of the second amplitude value of the grid and the detection value is less than or equal to a preset threshold value;

in the range of the maximum acting distance of the sea clutter of each sector, for each grid, comparing the second amplitude value of the grid with the minimum value in the second amplitude values of other grids, wherein the second amplitude value of the grid is less than or equal to the minimum value in the second amplitude values of other grids, and the other grids are all grids which are positioned in front of the current grid in the distance dimension of the current sector;

if the two preset conditions are met simultaneously, the amplitude values of all sampling points in the grid are reserved.

As a further improvement of the present invention, the determining an adjustment parameter based on the histogram of amplitude distribution of sea clutter and determining a sea clutter gain value based on the adjustment parameter includes:

searching an amplitude value corresponding to the probability just greater than a preset probability in the sea clutter amplitude distribution histogram as an adjustment parameter V1;

and determining a sea clutter gain value corresponding to the antenna rotation current circle based on the adjusting parameter V1.

As a further improvement of the present invention, the determining the sea clutter gain value corresponding to the current rotation circle of the antenna based on the adjustment parameter V1 includes:

when the antenna rotates the current circle, the sea clutter gain value corresponding to the previous circle of the antenna rotation and the adjusting parameter V1 are weighted to obtain the sea clutter gain value corresponding to the current circle of the antenna rotation

Wherein, in the step (A),

the gain value of the sea clutter corresponding to the ith turn of the antenna is represented,

the corresponding sea clutter gain value of the i-1 th circle of the antenna rotation is represented, and g and h respectively represent weighting coefficients.

The invention also provides a system for automatically inhibiting the sea clutter of the navigation radar, which comprises:

the grid division module is used for carrying out grid division on a scanning range, the grid division module is divided into a plurality of grids in the direction dimension and the distance dimension, each grid comprises a plurality of sampling points, a plurality of circles concentric with a central point are arranged in the direction dimension, two adjacent concentric circles form a distance ring, a plurality of rays diverged from the central point are arranged in the distance dimension, and two adjacent rays form a sector;

the amplitude counting module is used for determining a first amplitude value of each grid contained in the current circle, a noise amplitude value corresponding to the current circle of antenna rotation, a sea clutter maximum action distance of each sector and a corresponding sampling point number according to the positions of all sampling points falling in the scanning range of the current circle of antenna rotation;

the basic detection curve module is used for acquiring a second amplitude value of each grid based on the first amplitude value of the grid around each grid within the maximum action distance range of the sea clutter of each sector, and processing the second amplitude value of each grid to obtain a sea clutter basic detection curve;

the sea clutter gain adjusting module is used for determining whether amplitude values of all sampling points in each grid are reserved or not, forming a corresponding sea clutter amplitude distribution histogram based on the amplitude values of all the sampling points in each reserved grid, determining an adjusting parameter based on the sea clutter amplitude distribution histogram, and determining a sea clutter gain value based on the adjusting parameter;

and the final detection curve module is used for adding the sea clutter gain value to the sea clutter basic detection curve for each sector and performing smoothing processing to obtain a sea clutter final detection curve.

As a further improvement of the present invention, the scanning range is divided into a plurality of azimuth cells in an azimuth dimension, and each azimuth cell is divided into a plurality of distance cells in a distance dimension, and the amplitude statistic module includes:

wherein a and b represent weighting coefficients, respectively,

averaging amplitude values of all sampling points in each range ringTaking the minimum value in the average value of the amplitudes of all the distance rings as a noise reference amplitude value of the antenna rotating current circle, and carrying out weighting processing on the noise reference amplitude value to obtain a noise amplitude value,

wherein c and d represent weighting coefficients, respectively,

representing the noise amplitude value of the i-th turn of the antenna,

representing the noise amplitude value of the i-1 th turn of the antenna;

wherein e and f represent weighting coefficients, respectively,

As a further improvement of the present invention, the basic detection curve module comprises:

wherein, in the step (A),

a second amplitude value representing the current grid,

a first amplitude value representing a grid on the current grid,

a first amplitude value representing a grid next to the current grid,

representing a first amplitude value of a grid preceding the current grid,

representing a first magnitude value of a grid subsequent to the current grid;

As a further improvement of the present invention, the sea clutter gain adjusting module comprises: and when a preset condition is met, determining amplitude value reservation of all sampling points in each grid.

As a further improvement of the present invention, the sea clutter gain adjusting module comprises:

Wherein, in the step (A),

The invention also provides an electronic device comprising a memory and a processor, the memory storing one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the method.

The invention also provides a computer-readable storage medium having stored thereon a computer program for execution by a processor to perform the method.

The invention has the beneficial effects that: the method can provide a reasonable sea clutter gain value and obtain a sea clutter detection curve, can be matched with the environment of surrounding sea clutter in real time, can effectively suppress most of the sea clutter, and obtains a radar image with better quality.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

Fig. 1 is a schematic flow chart of a method for automatically suppressing sea clutter of a navigation radar according to an exemplary embodiment of the present invention;

FIG. 2 is a diagram illustrating meshing according to an exemplary embodiment of the present invention;

FIG. 3 is a diagram of four grids adjacent to a current grid in accordance with an exemplary embodiment of the present invention;

FIG. 4 is a schematic diagram of a sea clutter basic detection curve according to an exemplary embodiment of the present invention;

FIG. 5 is a graph of amplitude corresponding to tuning parameters in accordance with an exemplary embodiment of the present invention;

fig. 6 is a schematic diagram of a final sea clutter detection curve according to an exemplary embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, in the description of the present invention, the terms used are for illustrative purposes only and are not intended to limit the scope of the present invention. The terms "comprises" and/or "comprising" are used to specify the presence of stated elements, steps, operations, and/or components, but do not preclude the presence or addition of one or more other elements, steps, operations, and/or components. The terms "first," "second," and the like may be used to describe various elements, not necessarily order, and not necessarily limit the elements. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified. These terms are only used to distinguish one element from another. These and/or other aspects will become apparent to those of ordinary skill in the art in view of the following drawings, and the description of the embodiments of the present invention will be more readily understood by those of ordinary skill in the art. The drawings are only for purposes of illustrating the described embodiments of the invention. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated in the present application may be employed without departing from the principles described in the present application.

The method for automatically suppressing the sea clutter of the navigation radar in the embodiment of the invention is shown in fig. 1, and comprises the following steps:

In the related art, the radar generally needs to set a signal threshold gain to suppress the sea clutter. For automatic threshold control, cfar detection is mostly adopted, the method calculates the amplitude of echoes around a target by setting a certain number of protection units and reference units, and a final threshold value is obtained according to the set false alarm probability and the methods of unit selection large, unit selection small and unit selection average. And comparing the detected echo with the threshold value, if the detected echo is larger than the threshold value, determining that the echo is detected, and otherwise, determining that no echo is output. The cfar detection technology focuses on setting the false alarm probability and the number of protection units, while for a navigation radar, land is also one of targets to be detected, and the number of protection units of the targets is difficult to set. In addition, the sea clutter is suppressed by the sea clutter gain, and the distribution characteristic of the sea clutter amplitude needs to be considered. The distribution of the sea clutter is different in different sea areas and sea conditions, and it is difficult to use an amplitude distribution to describe the actual amplitude distribution characteristics of the clutter.

According to the method, the amplitude distribution of the sea clutter is obtained in real time, and the obtained detection curve is a result obtained through multi-frame real-time weighting calculation so as to reflect the average trend of the amplitude of the sea clutter changing along with the distance. And finding out more accurate sea clutter gain according to the preset probability, automatically adding the sea clutter gain to the sea clutter basic curve, and performing smoothing treatment to obtain a final sea clutter detection curve, so that most of the sea clutter can be removed, and a radar image with better quality can be obtained. The obtained final sea clutter detection curve has strong adaptability and can be suitable for different sea areas and different sea conditions. For different sea clutter amplitude distributions, such as Rayleigh distribution, Weibull distribution, normal logarithmic distribution and K distribution, the curve adjusted by the method is similar to the change rule of the sea clutter, the curve is kept to be reduced, the curve can be consistent with the real-time change trend of the sea clutter, and the method can be suitable for detecting low, small and slow targets.

In an alternative embodiment, the scanning range is divided into a plurality of azimuth cells in the azimuth dimension, each azimuth cell is divided into a plurality of range cells in the range dimension,

wherein a and b represent weighting coefficients, respectively,

averaging the amplitude values of all sampling points in each distance ring, taking the minimum value in the average values of the amplitudes of all distance rings as a noise reference amplitude value of the current circle of antenna rotation, performing weighting processing on the noise reference amplitude value to obtain a noise amplitude value,

wherein c and d represent weighting coefficients, respectively,

representing the noise amplitude value of the i-th turn of the antenna,

representing the noise amplitude value of the i-1 th turn of the antenna;

wherein e and f represent weighting coefficients, respectively,

The scanning range is divided into a plurality of azimuth units in the azimuth dimension, each distance unit in the azimuth unit is divided into a plurality of distance units in the distance dimension, and one distance unit in each azimuth unit forms a grid unit, namely the grid. As shown in fig. 2, the azimuth dimension is divided into 512 azimuth cells, for example, and each circle is divided into 512 azimuth cells, and each range cell in the range dimension contains 30 sampling points, for example. It will be appreciated that for each revolution of the antenna, a frame of radar image is acquired. When the amplitude values of the grid are weighted, a multi-frame recursion processing process is required. In the process of recursion, canAnd when the antenna rotates for the 1 st circle, taking the average value of the amplitude values of all sampling points in each grid as the initial grid amplitude value. The current frame weighting coefficients a and b, which may be the same or different, may be adaptively designed, for example,

the present invention is not particularly limited. Of course, the weighting coefficient a of the current frame (antenna rotation ith turn) is the same as the weighting coefficient a of the previous frame (antenna rotation ith-1 turn), and the weighting coefficient b of the current frame (antenna rotation ith turn) is the same as the weighting coefficient b of the previous frame (antenna rotation ith-1 turn).

When the noise amplitude value weighting processing is performed, the amplitude average value of all sampling points when the antenna rotates the 1 st circle can be used as the initial noise amplitude value. The weighting coefficients c and d for the current turn may be the same or different and may be adaptively designed, for example,

the present invention is not particularly limited. Of course, the weighting coefficient c is the same for the current frame (antenna rotation ith turn) and the previous frame (antenna rotation ith-1 turn), and the weighting coefficient d is the same for the current frame (antenna rotation ith turn) and the previous frame (antenna rotation ith-1 turn).

The maximum action distance of the sea clutter is carried out by sectors, and each sector needs to determine the number of sampling points corresponding to the maximum action distance of the sea clutter. When comparing the first amplitude value of each grid of the current sector with the noise amplitude value, for example, it may be determined that the first amplitude values of 5 continuous grids are all smaller than the noise amplitude value, and assuming that the number of distance units where the first grid of the 5 continuous grids is located is n1, the maximum acting distance of the sea clutter of the current sector is the distance from the first distance unit of the current sector to the n 1-th distance unit, and the number of sampling points in the maximum acting distance range of the sea clutter is n1 × 30. The number of sampling points of each distance unit is 30, which is an exemplary illustration, and the number of continuous grids and the number of sampling points of each distance unit are not specifically limited in the present invention.

Number of sampling points within the range of maximum acting distance to sea clutterWhen weighting processing is carried out, the number of sampling points of the sea clutter maximum acting distance of the current sector p when the antenna rotates the 1 st circle can be used as the number of initial sampling points. The weighting factors e and f for the current turn may be the same or different and may be adaptively designed, for example,

the present invention is not particularly limited. Of course, the current frame (antenna rotation ith turn) is the same as the previous frame (antenna rotation ith-1 st turn) e, and the current frame (antenna rotation ith turn) is the same as the previous frame (antenna rotation ith-1 st turn) f.

An optional implementation manner, where in the range of the maximum acting distance of the sea clutter of each sector, the second amplitude value of each grid is obtained based on the first amplitude value of the grid around each grid, and the second amplitude value of each grid is processed to obtain the sea clutter basic detection curve, includes:

wherein, in the step (A),

a second amplitude value representing the current grid,

a first amplitude value representing a grid on the current grid,

a first amplitude value representing a grid next to the current grid,

representing a first amplitude value of a grid preceding the current grid,

representing the current grid one afterA first amplitude value of the grid;

It is understood that the first scan line of each sector is counted with the sea clutter basic detection curve, and thus, once per sector. For each sector, the first amplitude value of each grid is obtained by the method according to each sampling point in the maximum action distance range of the sea clutter, and the specific obtaining mode of the first amplitude value is not described herein again. And performing secondary processing on the first amplitude value of each grid, and performing weighted average on the first amplitude values of four adjacent grids of the current grid to obtain a second amplitude value of the current grid. As shown in fig. 3, the four adjacent grids of the current grid are respectively a previous grid, a next grid, a previous grid and a next grid. The secondary processing process can improve the effectiveness of data processing.

When each second amplitude value is processed by folding, for example, a sea clutter basic detection curve can be obtained by linear regression or other methods

. As shown in fig. 4, the square broken line represents the second amplitude value of each grid, and the broken line represents the sea clutter basic detection curve obtained after the broken line processing. Considering that the amplitude value is smaller as the distance between the sea clutter is farther, the slope between the adjacent grids is smaller than or equal to 0, the descending trend of the basic detection curve of the sea clutter can be seen, the change rule of the sea clutter is similar to that of the sea clutter, and the land and the target in the sea clutter can be detected.

In an optional embodiment, the determining whether amplitude values of all sampling points in each grid remain, and forming a corresponding sea clutter amplitude distribution histogram based on the amplitude values of the remaining sampling points includes:

In an alternative embodiment, the preset conditions include the following two conditions:

It is understood that the second amplitude value counted in each grid is the result of multi-frame de-clutter correlation. Since each sampling point in the grid has a corresponding value on the sea clutter basic detection curve, and a grid includes 30 sampling points, for example, the second amplitude value of the grid needs to be compared with the detection value of the sea clutter basic detection curve corresponding to the first sampling point falling in the grid. And in the range of the maximum action distance of the sea clutter, if the amplitude value corresponding to the first sampling point subtracted from the second amplitude value of the grid is larger than a preset threshold (for example, 10), which indicates that a target exists, the second amplitude value of the grid is not counted.

It will also be appreciated that the amplitude of the sea clutter is related to the distance, the further the distance, the smaller the amplitude, and therefore the second amplitude value of the current grid needs to be compared with the minimum of the second amplitude values of the other grids. The other grids are all grids located before the current grid in the distance dimension of the current sector, for example, the sector has 6 grids, the current grid is the 5 th grid, and the 1 st, 2 nd, 3 th and 4 th grids are used as the other grids. And when the second amplitude value of the current grid is larger than the minimum value in the second amplitude values of other grids, the second amplitude value of the current grid is not counted. Therefore, the influence of small targets can be eliminated, and the overall descending trend of the sea clutter amplitude is ensured.

An optional embodiment, the determining an adjustment parameter based on the histogram of sea clutter amplitude distribution, and determining a sea clutter gain value based on the adjustment parameter, comprises:

The preset probability is a preset threshold, and when the sea clutter amplitude distribution histogram is just greater than the amplitude value corresponding to the preset probability, the amplitude value is used as an adjustment parameter, as shown in fig. 5, which is V1.

In an optional embodiment, the determining, based on the adjustment parameter V1, a sea clutter gain value corresponding to a current rotation circle of the antenna includes:

Wherein, in the step (A),

By performing multi-frame weighting processing on the sea clutter gain value, the situation that the sea clutter gain value changes too fast or an abnormal value exists can be prevented. The current frame weighting coefficients g and h, which may be the same or different, may be adaptively designed, e.g.,

the present invention is not particularly limited. Of course, the weighting coefficients g of the current frame (antenna rotation ith turn) and the previous frame (antenna rotation ith-1 turn) are the same, and the weighting coefficients h of the current frame (antenna rotation ith turn) and the previous frame (antenna rotation ith-1 turn) are the same.

Basic detection curve of sea clutter

And adding the sea clutter gain value and performing smoothing treatment to obtain a final sea clutter detection curve. As shown in fig. 6, the smoothed curve is the final sea clutter detection curve obtained after processing, and the amplitude distribution characteristic of the sea clutter is reflected by subtracting the smoothed curve from the amplitude of the sea clutter sampling point. It can be seen that the final detection curve of the sea clutter keeps a descending trend, the change rule of the sea clutter is similar to that of the sea clutter, and noise and the sea clutter can be effectively suppressed.

The method can automatically give a sea clutter gain value after the antenna rotates one circle, and obtain a sea clutter detection curve, and can be matched with the environment of the surrounding sea clutter in real time. After the automatic mode of the radar is switched, the radar display image after sea clutter suppression can be rapidly seen, and meanwhile, the automatic sea clutter gain value can also provide reference for manually adjusting the sea clutter gain.

The embodiment of the invention discloses a system for automatically inhibiting sea clutter of a navigation radar, which comprises:

The system obtains the amplitude distribution of the sea clutter in real time, and the obtained detection curve is a result obtained through multi-frame real-time weighting calculation so as to reflect the average trend of the amplitude of the sea clutter changing along with the distance. And finding out more accurate sea clutter gain according to the preset probability, automatically adding the sea clutter gain to the sea clutter basic curve, and performing smoothing treatment to obtain a final sea clutter detection curve, so that most of the sea clutter can be removed, and a radar image with better quality can be obtained. The obtained final sea clutter detection curve has strong adaptability and can be suitable for different sea areas and different sea conditions. For different sea clutter amplitude distributions, such as Rayleigh distribution, Weibull distribution, normal logarithmic distribution and K distribution, the curve adjusted by the system is close to the change rule of the sea clutter, the curve is kept to be reduced, the curve can be consistent with the real-time change trend of the sea clutter, and the system can be suitable for detecting low, small and slow targets.

In an alternative embodiment, the scan range is divided into a plurality of azimuth cells in an azimuth dimension, and each azimuth cell is divided into a plurality of range cells in a range dimension, and the amplitude statistics module includes:

wherein a and b represent weighting coefficients, respectively,

the nth azimuth unit representing the ith turn of the antennaThe reference amplitude value of the grid in which the range cell is located,

wherein c and d represent weighting coefficients, respectively,

representing the noise amplitude value of the i-th turn of the antenna,

representing the noise amplitude value of the i-1 th turn of the antenna;

wherein e and f represent weighting coefficients, respectively,

The scanning range is divided into a plurality of azimuth units in the azimuth dimension, each distance unit in the azimuth unit is divided into a plurality of distance units in the distance dimension, and one distance unit in each azimuth unit forms a grid unit, namely the grid. As shown in fig. 2, the azimuth dimension is divided into 512 azimuth cells, for example, and each circle is divided into 512 azimuth cells, and each range cell in the range dimension contains 30 sampling points, for example. It will be appreciated that for each revolution of the antenna, a frame of radar image is acquired. When the amplitude values of the grid are weighted, a multi-frame recursion processing process is required. In the recursion process, when the antenna rotates for the 1 st turn, the average value of the amplitude values of all sampling points in each grid can be used as the initial grid amplitude value. The current frame weighting coefficients a and b, which may be the same or different, may be adaptively designed, for example,

In the noise amplitude value weighting process, the number of days may be setAnd when the line rotates for the 1 st circle, the average value of the amplitudes of all the sampling points is used as the initial noise amplitude value. The weighting coefficients c and d for the current turn may be the same or different and may be adaptively designed, for example,

When the sampling point number in the range of the maximum acting distance of the sea clutter is weighted, the sampling point number of the maximum acting distance of the sea clutter of the current sector p is used as the initial sampling point number when the antenna rotates the 1 st circle. The weighting factors e and f for the current turn may be the same or different and may be adaptively designed, for example,

the present invention is not particularly limited. Of course, the current frame (antenna rotation ith turn) is the same as the previous frame (antenna rotation ith-1 turn) e, and the current frame (antenna rotation ith turn) is the same as the previous frame (antenna rotation ith-1 turn) f, and the invention is not limited in particular.

In an alternative embodiment, the basic detection curve module comprises:

wherein, in the step (A),

a second amplitude value representing the current grid,

a first amplitude value representing a grid on the current grid,

a first amplitude value representing a grid next to the current grid,

representing a first amplitude value of a grid preceding the current grid,

representing a first magnitude value of a grid subsequent to the current grid;

In an alternative embodiment, the sea clutter gain adjustment module comprises: and when a preset condition is met, determining amplitude value reservation of all sampling points in each grid.

In an alternative embodiment, the sea clutter gain adjustment module comprises:

Wherein, in the step (A),

Basic detection curve of sea clutter

And adding the sea clutter gain value and performing smoothing treatment to obtain a final sea clutter detection curve. As shown in fig. 6, the smoothed curve is the final sea clutter detection curve obtained after processing, and the amplitude distribution characteristic of the sea clutter is reflected by subtracting the smoothed curve from the amplitude of the sea clutter sampling point. It can be seen that the final detection curve of the sea clutter keeps the descending trend and the change rule of the sea clutterAnd the noise and the sea clutter can be effectively suppressed.

The system can automatically give a sea clutter gain value after the antenna rotates one circle, and obtain a sea clutter detection curve, so that the system can be matched with the environment of surrounding sea clutter in real time. After the automatic mode of the radar is switched, the radar display image after sea clutter suppression can be rapidly seen, and meanwhile, the automatic sea clutter gain value can also provide reference for manually adjusting the sea clutter gain.

The disclosure also relates to an electronic device comprising a server, a terminal and the like. The electronic device includes: at least one processor; a memory communicatively coupled to the at least one processor; and a communication component communicatively coupled to the storage medium, the communication component receiving and transmitting data under control of the processor; wherein the memory stores instructions executable by the at least one processor to implement the method of the above embodiments.

In an alternative embodiment, the memory is used as a non-volatile computer-readable storage medium for storing non-volatile software programs, non-volatile computer-executable programs, and modules. The processor executes various functional applications of the device and data processing, i.e., implements the method, by executing nonvolatile software programs, instructions, and modules stored in the memory.

The memory may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the storage data area may store a list of options, etc. Further, the memory may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device. In some embodiments, the memory optionally includes memory located remotely from the processor, and such remote memory may be connected to the external device via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

One or more modules are stored in the memory and, when executed by the one or more processors, perform the methods of any of the method embodiments described above.

The product can execute the method provided by the embodiment of the application, has corresponding functional modules and beneficial effects of the execution method, and can refer to the method provided by the embodiment of the application without detailed technical details in the embodiment.

The present disclosure also relates to a computer-readable storage medium for storing a computer-readable program for causing a computer to perform some or all of the above-described method embodiments.

That is, as can be understood by those skilled in the art, all or part of the steps in the method for implementing the embodiments described above may be implemented by a program instructing related hardware, where the program is stored in a storage medium and includes several instructions to enable a device (which may be a single chip, a chip, or the like) or a processor (processor) to execute all or part of the steps of the method described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Furthermore, those of ordinary skill in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

It will be understood by those skilled in the art that while the present invention has been described with reference to exemplary embodiments, various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A method for automatically suppressing sea clutter of a navigation radar, the method comprising:

determining whether the amplitude value of the sampling point in each grid is reserved, and forming a corresponding sea clutter amplitude distribution histogram based on the reserved amplitude value of the sampling point of each grid;

2. The method of claim 1, wherein the scan range is divided into a plurality of azimuth cells in an azimuth dimension, each azimuth cell is divided into a plurality of range cells in a range dimension,

wherein a and b represent weighting coefficients, respectively,

averaging the amplitude values of all sampling points in each distance ring, and averaging the minimum amplitude values of all distance ringsThe value is taken as a noise reference amplitude value of the antenna rotating current circle, and the noise reference amplitude value is weighted to obtain a noise amplitude value,

wherein c and d represent weighting coefficients, respectively,

representing the noise amplitude value of the i-th turn of the antenna,

representing the noise amplitude value of the i-1 th turn of the antenna;

wherein e and f represent weighting coefficients, respectively,

sample corresponding to maximum action distance of sea clutter of p-th sector of i-th circle of antenna rotationThe number of points is counted,

3. The method according to claim 1, wherein the obtaining the second amplitude value of each grid based on the first amplitude value of the grid around each grid within the maximum range of the sea clutter contribution distance of each sector and processing the second amplitude value of each grid to obtain the sea clutter basic detection curve comprises:

wherein, in the step (A),

a second amplitude value representing the current grid,

a first amplitude value representing a grid on the current grid,

a first amplitude value representing a grid next to the current grid,

representing a first amplitude value of a grid preceding the current grid,

representing a first magnitude value of a grid subsequent to the current grid;

performing fold line processing on the second amplitude value of each grid, wherein during the fold line processing, if the second amplitude value of the current grid is larger than the second amplitude value of the previous gridAnd the slope of the broken line between the two grids is 0, and a sea clutter basic detection curve with a descending trend is obtained, wherein,

4. The method of claim 1, wherein the determining whether amplitude values of all sample points in each grid remain and forming a corresponding sea clutter amplitude distribution histogram based on the retained amplitude values of the sample points comprises:

5. The method of claim 4, wherein the preset conditions include two of:

6. The method of claim 1, wherein the determining an adjustment parameter based on the histogram of sea clutter amplitude distribution and determining a sea clutter gain value based on the adjustment parameter comprises:

7. The method of claim 6, wherein the determining a sea clutter gain value corresponding to the current circle of antenna rotation based on the adjustment parameter V1 comprises:

Wherein, in the step (A),

8. A system for automatically suppressing sea clutter of a navigation radar, the system comprising:

9. An electronic device comprising a memory and a processor, wherein the memory is configured to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the method of any one of claims 1-7.

10. A computer-readable storage medium, on which a computer program is stored, the computer program being executable by a processor for implementing the method according to any one of claims 1-7.